STABLE TELOCENTRIC CHROMOSOMES PRODUCED FOLLOWING CENTRIC MISDIVISION IN MYRMELEOTETTIX MACULATUS (THUNB)

The standard complement of Myrmeleotettix maculatus includes a pair of L3 metacentric chromosomes but throughout the germ line of a structurally mutant male individual one of these had been replaced by two telocentrics. These chromosomes divided normally at mitosis and at meiosis paired completely with the arms of the remaining L3. There was no tendency for the two terminal centromeres to fuse. At first anaphase the two rods usually segregated from the metacentric which resulted in the formation of a high percentage of balanced gametes. On the basis of this evidence and the morphological appearance of the centric region it has been concluded that the derived telocentrics evolved following misdivision through the inner zone of the metacentric centromere. In view of their apparent stability it has been proposed that, contrary to certain beliefs, centric fission may have played an important role during karyotype evolution in the Acrididae. © 1969 Springer-Verlag.